Loans and Leases (Composition Of The Loans And Leases Outstanding At By Credit Quality Indicator) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012		Dec. 31, 2011		Mar. 31, 2011
Noncovered loans	$ 11,489,529	[1]	$ 11,581,637	[2]	$ 11,392,351	[1]
Covered under loss share agreements	2,183,869	[1]	2,362,152	[2]	2,658,134	[1]
Commercial Mortgage [Member]
Noncovered loans	7,830,041		7,866,572		7,546,718
Covered under loss share agreements	1,745,709		1,872,685		2,171,294
Non-Commercial Loans [Member]
Noncovered loans	3,659,488		3,715,065		3,845,633
Covered under loss share agreements	438,160		489,467		486,840
Construction and Land Development [Member] | Commercial Mortgage [Member]
Noncovered loans	346,557		381,163		373,769
Covered under loss share agreements	310,601		338,873		402,316
Construction and Land Development [Member] | Non-Commercial Loans [Member]
Noncovered loans	132,677		137,271		145,864
Covered under loss share agreements	85,555		105,536		111,425
Commercial Mortgage [Member] | Commercial Mortgage [Member]
Noncovered loans	5,127,948		5,104,993		4,763,393
Covered under loss share agreements	1,195,541		1,260,589		1,432,632
Commercial Mortgage [Member] | Commercial Mortgage [Member]
Noncovered loans	1,739,724		1,764,407		1,792,042
Other Commercial Real Estate [Member] | Commercial Mortgage [Member]
Noncovered loans	150,316		144,771		147,150
Covered under loss share agreements	144,978		158,394		163,305
Commercial And Industrial [Member] | Commercial Mortgage [Member]
Noncovered loans	1,739,724		1,764,407		1,792,042
Covered under loss share agreements	93,261		113,442		171,041
Lease Financing [Member] | Commercial Mortgage [Member]
Noncovered loans	315,704		312,869		295,994
Covered under loss share agreements	45		57		271
Other Loans [Member] | Commercial Mortgage [Member]
Noncovered loans	149,792		158,369		174,370
Covered under loss share agreements	1,283		1,330		1,729
Residential Mortgage [Member] | Non-Commercial Loans [Member]
Noncovered loans	793,612		784,118		808,650
Covered under loss share agreements	298,538		327,568		347,393
Revolving Mortgage [Member] | Non-Commercial Loans [Member]
Noncovered loans	2,282,138		2,296,306		2,299,668
Covered under loss share agreements	50,016		51,552		23,409
Consumer [Member] | Non-Commercial Loans [Member]
Noncovered loans	451,061		497,370		591,451
Covered under loss share agreements	4,051		4,811		4,613
Pass [Member] | Commercial Mortgage [Member]
Noncovered loans	7,195,417		7,232,547		6,883,895
Pass [Member] | Construction and Land Development [Member] | Commercial Mortgage [Member]
Noncovered loans	303,018		332,742		316,395
Pass [Member] | Commercial Mortgage [Member] | Commercial Mortgage [Member]
Noncovered loans	4,744,063		4,749,254		4,403,652
Pass [Member] | Other Commercial Real Estate [Member] | Commercial Mortgage [Member]
Noncovered loans	136,776		130,586		133,931
Pass [Member] | Commercial And Industrial [Member] | Commercial Mortgage [Member]
Noncovered loans	1,554,112		1,556,651		1,571,193
Pass [Member] | Lease Financing [Member] | Commercial Mortgage [Member]
Noncovered loans	309,681		306,225		285,699
Pass [Member] | Other Loans [Member] | Commercial Mortgage [Member]
Noncovered loans	147,767		157,089		173,025
Special Mention [Member] | Commercial Mortgage [Member]
Noncovered loans	311,248		287,788		309,400
Special Mention [Member] | Construction and Land Development [Member] | Commercial Mortgage [Member]
Noncovered loans	20,097		18,973		22,416
Special Mention [Member] | Commercial Mortgage [Member] | Commercial Mortgage [Member]
Noncovered loans	243,495		220,235		232,019
Special Mention [Member] | Other Commercial Real Estate [Member] | Commercial Mortgage [Member]
Noncovered loans	6,805		5,821		7,415
Special Mention [Member] | Commercial And Industrial [Member] | Commercial Mortgage [Member]
Noncovered loans	35,497		36,951		40,023
Special Mention [Member] | Lease Financing [Member] | Commercial Mortgage [Member]
Noncovered loans	3,336		4,537		6,228
Special Mention [Member] | Other Loans [Member] | Commercial Mortgage [Member]
Noncovered loans	2,018		1,271		1,299
Substandard [Member] | Commercial Mortgage [Member]
Noncovered loans	187,690		196,325		192,164
Substandard [Member] | Construction and Land Development [Member] | Commercial Mortgage [Member]
Noncovered loans	21,297		28,793		32,864
Substandard [Member] | Commercial Mortgage [Member] | Commercial Mortgage [Member]
Noncovered loans	130,815		129,391		119,229
Substandard [Member] | Other Commercial Real Estate [Member] | Commercial Mortgage [Member]
Noncovered loans	6,068		7,794		5,271
Substandard [Member] | Commercial And Industrial [Member] | Commercial Mortgage [Member]
Noncovered loans	27,057		28,240		30,992
Substandard [Member] | Lease Financing [Member] | Commercial Mortgage [Member]
Noncovered loans	2,453		2,107		3,796
Substandard [Member] | Other Loans [Member] | Commercial Mortgage [Member]
Noncovered loans	0		0		12
Doubtful [Member] | Commercial Mortgage [Member]
Noncovered loans	10,450		2,201		9,952
Doubtful [Member] | Construction and Land Development [Member] | Commercial Mortgage [Member]
Noncovered loans	1,821		17		2,094
Doubtful [Member] | Commercial Mortgage [Member] | Commercial Mortgage [Member]
Noncovered loans	6,588		1,164		6,004
Doubtful [Member] | Other Commercial Real Estate [Member] | Commercial Mortgage [Member]
Noncovered loans	365		377		401
Doubtful [Member] | Commercial And Industrial [Member] | Commercial Mortgage [Member]
Noncovered loans	1,676		643		1,182
Doubtful [Member] | Lease Financing [Member] | Commercial Mortgage [Member]
Noncovered loans	0		0		271
Doubtful [Member] | Other Loans [Member] | Commercial Mortgage [Member]
Noncovered loans	0		0		0
Ungraded [Member] | Commercial Mortgage [Member]
Noncovered loans	125,236		147,711		151,307
Ungraded [Member] | Construction and Land Development [Member] | Commercial Mortgage [Member]
Noncovered loans	324		638		0
Ungraded [Member] | Commercial Mortgage [Member] | Commercial Mortgage [Member]
Noncovered loans	2,987		4,949		2,489
Ungraded [Member] | Other Commercial Real Estate [Member] | Commercial Mortgage [Member]
Noncovered loans	302		193		132
Ungraded [Member] | Commercial And Industrial [Member] | Commercial Mortgage [Member]
Noncovered loans	121,382		141,922		148,652
Ungraded [Member] | Lease Financing [Member] | Commercial Mortgage [Member]
Noncovered loans	234		0		0
Ungraded [Member] | Other Loans [Member] | Commercial Mortgage [Member]
Noncovered loans	7		9		34
Covered Loans [Member]
Covered under loss share agreements	2,183,869		2,362,152		2,658,134
Covered Loans [Member] | Construction and Land Development [Member] | Commercial Mortgage [Member]
Covered under loss share agreements	310,601		338,873		402,316
Covered Loans [Member] | Construction and Land Development [Member] | Non-Commercial Loans [Member]
Covered under loss share agreements	85,555		105,536		111,425
Covered Loans [Member] | Commercial Mortgage [Member]
Covered under loss share agreements	1,195,541		1,260,589		1,432,632
Covered Loans [Member] | Other Commercial Real Estate [Member]
Covered under loss share agreements	144,978		158,394		163,305
Covered Loans [Member] | Commercial And Industrial [Member]
Covered under loss share agreements	93,261		113,442		171,041
Covered Loans [Member] | Lease Financing [Member]
Covered under loss share agreements	45		57		271
Covered Loans [Member] | Residential Mortgage [Member]
Covered under loss share agreements	298,538		327,568		347,393
Covered Loans [Member] | Revolving Mortgage [Member]
Covered under loss share agreements	50,016		51,552		23,409
Covered Loans [Member] | Consumer And Other [Member]
Covered under loss share agreements	5,334		6,141		6,342
Covered Loans [Member] | Pass [Member]
Covered under loss share agreements	731,002		743,881		815,658
Covered Loans [Member] | Pass [Member] | Construction and Land Development [Member] | Commercial Mortgage [Member]
Covered under loss share agreements	31,445		29,321		76,319
Covered Loans [Member] | Pass [Member] | Construction and Land Development [Member] | Non-Commercial Loans [Member]
Covered under loss share agreements	7,020		4,958		4,217
Covered Loans [Member] | Pass [Member] | Commercial Mortgage [Member]
Covered under loss share agreements	392,233		397,526		574,681
Covered Loans [Member] | Pass [Member] | Other Commercial Real Estate [Member]
Covered under loss share agreements	56,689		49,259		60,238
Covered Loans [Member] | Pass [Member] | Commercial And Industrial [Member]
Covered under loss share agreements	31,768		36,409		49,260
Covered Loans [Member] | Pass [Member] | Lease Financing [Member]
Covered under loss share agreements	45		57		2
Covered Loans [Member] | Pass [Member] | Residential Mortgage [Member]
Covered under loss share agreements	173,640		189,794		42,014
Covered Loans [Member] | Pass [Member] | Revolving Mortgage [Member]
Covered under loss share agreements	35,684		34,164		5,000
Covered Loans [Member] | Pass [Member] | Consumer And Other [Member]
Covered under loss share agreements	2,478		2,393		3,927
Covered Loans [Member] | Special Mention [Member]
Covered under loss share agreements	506,040		550,617		595,142
Covered Loans [Member] | Special Mention [Member] | Construction and Land Development [Member] | Commercial Mortgage [Member]
Covered under loss share agreements	89,243		92,758		112,999
Covered Loans [Member] | Special Mention [Member] | Construction and Land Development [Member] | Non-Commercial Loans [Member]
Covered under loss share agreements	14,263		13,394		23,127
Covered Loans [Member] | Special Mention [Member] | Commercial Mortgage [Member]
Covered under loss share agreements	335,020		348,482		339,385
Covered Loans [Member] | Special Mention [Member] | Other Commercial Real Estate [Member]
Covered under loss share agreements	26,736		33,754		31,218
Covered Loans [Member] | Special Mention [Member] | Commercial And Industrial [Member]
Covered under loss share agreements	21,376		32,257		49,511
Covered Loans [Member] | Special Mention [Member] | Lease Financing [Member]
Covered under loss share agreements	0		0		0
Covered Loans [Member] | Special Mention [Member] | Residential Mortgage [Member]
Covered under loss share agreements	18,054		25,464		36,430
Covered Loans [Member] | Special Mention [Member] | Revolving Mortgage [Member]
Covered under loss share agreements	802		3,566		2,225
Covered Loans [Member] | Special Mention [Member] | Consumer And Other [Member]
Covered under loss share agreements	546		942		247
Covered Loans [Member] | Substandard [Member]
Covered under loss share agreements	682,406		787,309		660,802
Covered Loans [Member] | Substandard [Member] | Construction and Land Development [Member] | Commercial Mortgage [Member]
Covered under loss share agreements	86,750		125,158		109,509
Covered Loans [Member] | Substandard [Member] | Construction and Land Development [Member] | Non-Commercial Loans [Member]
Covered under loss share agreements	53,919		72,349		66,829
Covered Loans [Member] | Substandard [Member] | Commercial Mortgage [Member]
Covered under loss share agreements	382,134		427,996		356,396
Covered Loans [Member] | Substandard [Member] | Other Commercial Real Estate [Member]
Covered under loss share agreements	51,918		58,351		46,393
Covered Loans [Member] | Substandard [Member] | Commercial And Industrial [Member]
Covered under loss share agreements	24,905		21,914		48,081
Covered Loans [Member] | Substandard [Member] | Lease Financing [Member]
Covered under loss share agreements	0		0		0
Covered Loans [Member] | Substandard [Member] | Residential Mortgage [Member]
Covered under loss share agreements	70,545		70,582		27,761
Covered Loans [Member] | Substandard [Member] | Revolving Mortgage [Member]
Covered under loss share agreements	11,153		9,863		5,509
Covered Loans [Member] | Substandard [Member] | Consumer And Other [Member]
Covered under loss share agreements	1,082		1,096		324
Covered Loans [Member] | Doubtful [Member]
Covered under loss share agreements	234,067		246,308		218,140
Covered Loans [Member] | Doubtful [Member] | Construction and Land Development [Member] | Commercial Mortgage [Member]
Covered under loss share agreements	99,747		87,936		98,757
Covered Loans [Member] | Doubtful [Member] | Construction and Land Development [Member] | Non-Commercial Loans [Member]
Covered under loss share agreements	10,353		14,835		17,252
Covered Loans [Member] | Doubtful [Member] | Commercial Mortgage [Member]
Covered under loss share agreements	85,993		84,871		62,984
Covered Loans [Member] | Doubtful [Member] | Other Commercial Real Estate [Member]
Covered under loss share agreements	9,635		17,030		24,833
Covered Loans [Member] | Doubtful [Member] | Commercial And Industrial [Member]
Covered under loss share agreements	15,212		22,862		3,795
Covered Loans [Member] | Doubtful [Member] | Lease Financing [Member]
Covered under loss share agreements	0		0		22
Covered Loans [Member] | Doubtful [Member] | Residential Mortgage [Member]
Covered under loss share agreements	9,934		13,833		7,484
Covered Loans [Member] | Doubtful [Member] | Revolving Mortgage [Member]
Covered under loss share agreements	2,377		3,959		1,966
Covered Loans [Member] | Doubtful [Member] | Consumer And Other [Member]
Covered under loss share agreements	816		982		1,047
Covered Loans [Member] | Ungraded [Member]
Covered under loss share agreements	30,354		34,037		368,392
Covered Loans [Member] | Ungraded [Member] | Construction and Land Development [Member] | Commercial Mortgage [Member]
Covered under loss share agreements	3,416		3,700		4,732
Covered Loans [Member] | Ungraded [Member] | Construction and Land Development [Member] | Non-Commercial Loans [Member]
Covered under loss share agreements	0		0		0
Covered Loans [Member] | Ungraded [Member] | Commercial Mortgage [Member]
Covered under loss share agreements	161		1,714		99,186
Covered Loans [Member] | Ungraded [Member] | Other Commercial Real Estate [Member]
Covered under loss share agreements	0		0		623
Covered Loans [Member] | Ungraded [Member] | Commercial And Industrial [Member]
Covered under loss share agreements	0		0		20,394
Covered Loans [Member] | Ungraded [Member] | Lease Financing [Member]
Covered under loss share agreements	0		0		247
Covered Loans [Member] | Ungraded [Member] | Residential Mortgage [Member]
Covered under loss share agreements	26,365		27,895		233,704
Covered Loans [Member] | Ungraded [Member] | Revolving Mortgage [Member]
Covered under loss share agreements	0		0		8,709
Covered Loans [Member] | Ungraded [Member] | Consumer And Other [Member]
Covered under loss share agreements	412		728		797
Noncovered Loans [Member]
Noncovered loans	11,489,529		11,581,637		11,392,351
Noncovered Loans [Member] | Non-Commercial Loans [Member]
Noncovered loans	3,659,488		3,715,065		3,845,633
Noncovered Loans [Member] | Construction and Land Development [Member] | Commercial Mortgage [Member]
Noncovered loans	346,557		381,163		373,769
Noncovered Loans [Member] | Construction and Land Development [Member] | Non-Commercial Loans [Member]
Noncovered loans	132,677		137,271		145,864
Noncovered Loans [Member] | Commercial Mortgage [Member]
Noncovered loans	5,127,948		5,104,993		4,763,393
Noncovered Loans [Member] | Other Commercial Real Estate [Member]
Noncovered loans	150,316		144,771		147,150
Noncovered Loans [Member] | Commercial And Industrial [Member]
Noncovered loans	1,739,724		1,764,407		1,792,042
Noncovered Loans [Member] | Lease Financing [Member]
Noncovered loans	315,704		312,869		295,994
Noncovered Loans [Member] | Other Loans [Member]
Noncovered loans	149,792		158,369		174,370
Noncovered Loans [Member] | Residential Mortgage [Member]
Noncovered loans	793,612		784,118		808,650
Noncovered Loans [Member] | Residential Mortgage [Member] | Non-Commercial Loans [Member]
Noncovered loans	793,612		784,118		808,650
Noncovered Loans [Member] | Revolving Mortgage [Member]
Noncovered loans	2,282,138		2,296,306		2,299,668
Noncovered Loans [Member] | Revolving Mortgage [Member] | Non-Commercial Loans [Member]
Noncovered loans	2,282,138		2,296,306		2,299,668
Noncovered Loans [Member] | Consumer [Member]
Noncovered loans	451,061		497,370		591,451
Noncovered Loans [Member] | Consumer [Member] | Non-Commercial Loans [Member]
Noncovered loans	451,061		497,370		591,451
Noncovered Loans [Member] | Current [Member] | Non-Commercial Loans [Member]
Noncovered loans	3,614,484		3,670,540		3,788,675
Noncovered Loans [Member] | Current [Member] | Construction and Land Development [Member] | Non-Commercial Loans [Member]
Noncovered loans	130,561		135,774		142,423
Noncovered Loans [Member] | Current [Member] | Residential Mortgage [Member] | Non-Commercial Loans [Member]
Noncovered loans	763,411		757,113		777,982
Noncovered Loans [Member] | Current [Member] | Revolving Mortgage [Member] | Non-Commercial Loans [Member]
Noncovered loans	2,274,091		2,286,511		2,287,726
Noncovered Loans [Member] | Current [Member] | Consumer [Member] | Non-Commercial Loans [Member]
Noncovered loans	446,421		491,142		580,544
Noncovered Loans [Member] | 31 to 60 Days Past Due [Member] | Non-Commercial Loans [Member]
Noncovered loans	19,043		19,539		29,928
Noncovered Loans [Member] | 31 to 60 Days Past Due [Member] | Construction and Land Development [Member] | Non-Commercial Loans [Member]
Noncovered loans	808		798		1,116
Noncovered Loans [Member] | 31 to 60 Days Past Due [Member] | Residential Mortgage [Member] | Non-Commercial Loans [Member]
Noncovered loans	14,001		11,790		16,439
Noncovered Loans [Member] | 31 to 60 Days Past Due [Member] | Revolving Mortgage [Member] | Non-Commercial Loans [Member]
Noncovered loans	2,349		3,437		5,462
Noncovered Loans [Member] | 31 to 60 Days Past Due [Member] | Consumer [Member] | Non-Commercial Loans [Member]
Noncovered loans	1,885		3,514		6,911
Noncovered Loans [Member] | 61 to 90 Days Past Due [Member] | Non-Commercial Loans [Member]
Noncovered loans	5,498		6,126		8,072
Noncovered Loans [Member] | 61 to 90 Days Past Due [Member] | Construction and Land Development [Member] | Non-Commercial Loans [Member]
Noncovered loans	446		127		364
Noncovered Loans [Member] | 61 to 90 Days Past Due [Member] | Residential Mortgage [Member] | Non-Commercial Loans [Member]
Noncovered loans	2,812		2,686		2,207
Noncovered Loans [Member] | 61 to 90 Days Past Due [Member] | Revolving Mortgage [Member] | Non-Commercial Loans [Member]
Noncovered loans	1,212		2,042		3,285
Noncovered Loans [Member] | 61 to 90 Days Past Due [Member] | Consumer [Member] | Non-Commercial Loans [Member]
Noncovered loans	1,028		1,271		2,216
Noncovered Loans [Member] | Over 90 Days Past Due [Member] | Non-Commercial Loans [Member]
Noncovered loans	20,463		18,860		18,958
Noncovered Loans [Member] | Over 90 Days Past Due [Member] | Construction and Land Development [Member] | Non-Commercial Loans [Member]
Noncovered loans	862		572		1,961
Noncovered Loans [Member] | Over 90 Days Past Due [Member] | Residential Mortgage [Member] | Non-Commercial Loans [Member]
Noncovered loans	13,388		12,529		12,022
Noncovered Loans [Member] | Over 90 Days Past Due [Member] | Revolving Mortgage [Member] | Non-Commercial Loans [Member]
Noncovered loans	4,486		4,316		3,195
Noncovered Loans [Member] | Over 90 Days Past Due [Member] | Consumer [Member] | Non-Commercial Loans [Member]
Noncovered loans	$ 1,727		$ 1,443		$ 1,780

[1] Unaudited

[2] Derived from 2011 Annual Report on Form 10-K.